{"affected":[{"defaultStatus":"unaffected","ecosystem":"npm","packageName":"@fastify/multipart","product":"@fastify/multipart","source":"CNA: openjs","vendor":"@fastify/multipart","versions":[{"lessThan":"10.1.7","status":"affected","version":"5.3.0","versionType":"semver"},{"status":"unaffected","version":"10.1.7","versionType":"semver"}]}],"cveId":"CVE-2026-117531","cwes":["CWE-400"],"description":"@fastify/multipart is the multipart form-data and file upload plugin for the Fastify web framework. In versions 5.3.0 through 10.1.6, the plugin does not propagate a parser error to the file stream when a request body ends inside a file part with no closing boundary, even though the Content-Length is complete, the client does not abort, and no file size limit is exceeded. The plugin destroys the in-progress file stream without an error, so a handler that iterates the request parts and performs asynchronous work before consuming the file attaches to a stream that never emits an error or end event, and the request never responds while the connection stays open. An unauthenticated remote client can repeat these malformed uploads against such a route to accumulate pending connections and exhaust server resources, so the impact is availability only and exploitation depends on the application using a delayed file consumer. The issue is fixed in @fastify/multipart 10.1.7, where the parser error is propagated to the file stream so a delayed consumer settles with an error instead of hanging, and users should upgrade to 10.1.7 or later. There is no workaround other than upgrading.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":5.9,"severity":"medium","source":"CNA: openjs","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},{"score":5.9,"severity":"medium","source":"NVD: ce714d77-add3-4f53-aff5-83d477b104bb","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}],"modifiedAt":1793618250853,"publishedAt":1793615558867,"references":[{"source":"CNA: openjs","tags":[],"url":"https://github.com/fastify/fastify-multipart/security/advisories/GHSA-5849-5m6q-9632"},{"source":"CNA: openjs","tags":[],"url":"https://cna.openjsf.org/security-advisories.html"},{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","tags":[],"url":"https://cna.openjsf.org/security-advisories.html"},{"source":"ce714d77-add3-4f53-aff5-83d477b104bb","tags":[],"url":"https://github.com/fastify/fastify-multipart/security/advisories/GHSA-5849-5m6q-9632"}],"remediation":[],"revision":"9f5e9f2a7cd20d8d2a6b84a29ef53f422dbb512ed9b20560bc85717c2b977a85","sources":[{"modifiedAt":1793615558867,"name":"CNA: openjs","retrievedAt":1793617700805,"url":"https://www.cve.org/CVERecord?id=CVE-2026-117531"},{"modifiedAt":1793618250853,"name":"NVD","retrievedAt":1793621820745,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117531"}],"ssvc":null,"status":"published","title":"@fastify/multipart vulnerable to Denial of Service via a malformed upload hanging delayed file consumers","updatedAt":1793621820745}